Method

Mix the flour, yeast and 1/2 tsp salt in a bowl. Make a well in the centre, add 200ml hand-hot water and the oil. Mix to a soft dough. Turn out onto a lightly floured surface and knead for 5 mins until smooth and silky. Return to the bowl, cover with a clean tea towel and leave to rise for 1 hr.

Meanwhile, boil the potatoes, then drain. Leave until cool enough to handle, then peel and cut into thin slices.

Put the spinach into a metal colander and pour over boiling water to just wilt the leaves. Press out excess water.

Knead the risen dough and roll out to line a 30 x 36cm shallow rectangular tin. Arrange spinach over the pastry to within 2cm of the edges. Lay the potatoes and taleggio alternately over the top, scatter with rosemary, and sprinkle parmesan over filling and edges. Drizzle with oil.

Leave to rise for 20 mins. Heat oven to 200C/180C fan/gas 6. Bake for 20-25 mins until pastry is golden and the topping melted. Serve cut into squares.